When a payment is declined, for reasons of privacy, credit card companies don't give the vendors (in this case, PetWill) a reason for why a payment is declined.

There are usually two common reasons which solve most of these declined errors:
  1. One is insufficient funds on the card.
  2. The second is that the card company flagged the payment as suspicious or potentially fraudulent.
Please contact the card company and ask them to authorize the transaction and then you can try again. For your security and privacy, we do not have any way to contact the credit card company on your behalf.